Final answer:
The primary cables in a suspension structure are the ones directly supporting the load.
Step-by-step explanation:
In a suspension structure, the primary cables are the ones directly supporting the load. These cables are usually pretensioned, meaning they are stretched before the load is applied. The pretension in the cables helps to counteract the weight of the load and keep the structure stable. Examples of suspension structures that use pretensioned cables include suspension bridges and cable-stayed bridges.